Glaucoma which is a sight threatening disease and is associated with raised intraocular pressure has been treated for a long time with beta blockers. Nowadays the drugs of choice are prostaglandin analogs. This study seeks to discover the effect of pleurotus tuberregium on raised intraocular pressure and to compare its effect on I.O.P with that of known glaucoma drugs. This study also seeks to find out at what concentration pleurotus is effective significantly on raised intraocular pressure